Need advice on camshaft
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Laughing Gas
Joined: Jan 2013
Posts: 1,015
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From: Gulf Coast, MS
Need advice on camshaft
Hopefully this weekend I will be purchasing a 300 with a 4bbl intake with a 500cfm carb and exhaust header (dont have specifics yet). I will be driving up first to make sure truck runs and everything is good and then help remove emgine to bring home. The engine only has 50k miles on it. The most work my truck will be doing is pulling my boat that is kinda heavy so I am thinking of putting a cam in to help with torque and would like some advice on which one to get. I do not have power brakes so I dont have that vacuum issue to worry about. So there it is...please bring on the questions and advice PLEASE!!
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Laughing Gas
Joined: Jan 2013
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Likes: 4
From: Gulf Coast, MS
Just ordered some 1.6 rockers with the kit so everything is new but I didnt think to ask about the nut size......damn
Just called back...should be good on that.
I looked up Comp cam and put in truck info and it suggested the 268 cam. As I was reading on another thread he was worried about losing some in the low end (torque?) with this cam which is what I am more concerned with as well.
Just called back...should be good on that.
I looked up Comp cam and put in truck info and it suggested the 268 cam. As I was reading on another thread he was worried about losing some in the low end (torque?) with this cam which is what I am more concerned with as well.
Last edited by maverick600; Feb 7, 2013 at 05:13 PM. Reason: More info
Postmaster
Joined: Mar 2005
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From: Earth
The Iskenderian Mil-A-Mor is probably as "max torque" as aftermarket cams come. The stock cam is good for low end as well, and some folks have used an adjustable timing set to advance the stock cam for even more low end. A little porting on the head and bumping up the compression ratio would also help.
Postmaster
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From: Earth
With what kit? The stock rockers are 1.6:1, fwiw.
Postmaster
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From: Earth
Ah so. Ford did use two different size rocker studs on the 300 through the years and the later models have bolt-down rockers in place of studs.
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Laughing Gas
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X2 on the Comp 260. The 252 is great too. Isky offers a 256 for good torque and mpg. Schnider Cams has a couple of nice grinds too, as does Cower.
If you go to the Summit Racing site, they have a great article, 'Bump stick basics,' I believe, that does a good job of explaining the various aspects of a cam. It helped me.
Basically, and someone correct me if I'm wrong, the higher the duration (how long the valves stay open)the higher the power/torque band of the cam goes--meaning the more lower end you loose.
If you go to the Summit Racing site, they have a great article, 'Bump stick basics,' I believe, that does a good job of explaining the various aspects of a cam. It helped me.
Basically, and someone correct me if I'm wrong, the higher the duration (how long the valves stay open)the higher the power/torque band of the cam goes--meaning the more lower end you loose.
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Laughing Gas
Joined: Jan 2013
Posts: 1,015
Likes: 4
From: Gulf Coast, MS
X2 on the Comp 260. The 252 is great too. Isky offers a 256 for good torque and mpg. Schnider Cams has a couple of nice grinds too, as does Cower.
If you go to the Summit Racing site, they have a great article, 'Bump stick basics,' I believe, that does a good job of explaining the various aspects of a cam. It helped me.
Basically, and someone correct me if I'm wrong, the higher the duration (how long the valves stay open)the higher the power/torque band of the cam goes--meaning the more lower end you loose.
If you go to the Summit Racing site, they have a great article, 'Bump stick basics,' I believe, that does a good job of explaining the various aspects of a cam. It helped me.
Basically, and someone correct me if I'm wrong, the higher the duration (how long the valves stay open)the higher the power/torque band of the cam goes--meaning the more lower end you loose.
Postmaster
Joined: Dec 2006
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From: Spokane, WA
I didn't lose anything with the Comp 260 but gained through the whole working rpm range.
FORDSIX PERFORMANCE • View topic - Will it pull?
FORDSIX PERFORMANCE • View topic - Will it pull?
Postmaster
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From: Earth
As a general rule of thumb, every 10 degree increase in cam duration will move the peak power up ~500 rpm.
For low end torque the cam needs to maximize cylinder pressure - i.e. the intake valve closes early (near when the piston reaches BDC) so the piston moving upwards compresses the mixture as much as possible and doesn't blow it out the intake.
You can gain back the low end with a more radical cam by raising the compression ratio. Search for the timing cards on the different cams you're interested in and plug the info into a dynamic compression calculator. That will show you how the different cams will affect low end performance.
For a more or less stock 300 (or any engine with something like a new intake/exhaust but close to factory compression) it's better to under cam than over cam. In a truck especially I'd prefer to lose a little on the top end if it means extra grunt off the line.
For low end torque the cam needs to maximize cylinder pressure - i.e. the intake valve closes early (near when the piston reaches BDC) so the piston moving upwards compresses the mixture as much as possible and doesn't blow it out the intake.
You can gain back the low end with a more radical cam by raising the compression ratio. Search for the timing cards on the different cams you're interested in and plug the info into a dynamic compression calculator. That will show you how the different cams will affect low end performance.
For a more or less stock 300 (or any engine with something like a new intake/exhaust but close to factory compression) it's better to under cam than over cam. In a truck especially I'd prefer to lose a little on the top end if it means extra grunt off the line.